1. Field of the Invention
The present invention relates to an image exposure method using a display panel, for exposing an image onto a photosensitive material by dividing the image into pixels which are arranged in a matrix pattern on the display panel and by adjusting amounts by which light is transmitted through or reflected at the pixels or an amount of emitted light.
2. Description of the Related Art
There has been proposed an image exposure method in which an image is formed by adjusting respective amounts by which light is transmitted through a plurality of pixels arranged in a matrix pattern on a liquid crystal display panel, and the light transmitted through the liquid crystal display panel is illuminated onto a photosensitive material (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 3-41868 and 4-323640).
In JP-A No. 3-41868, a system is disclosed in which a recording means allowing relative movement of a liquid crystal shutter and a photosensitive material respectively in the longitudinal direction and the transverse direction, and an image reading means are provided. Further, in JP-A No. 4-323640, a liquid crystal printer is disclosed in which an image is exposed with a liquid crystal display panel being two-dimensionally moved in a stepwise manner on the unit of (2n+1)P/2 with respect to a pitch P of pixels exposed onto the photosensitive material.
In this way, an original image is converted into a digital image by using a liquid crystal display function for display of the original image. For this reason, recording and processing of the image becomes easy.
On the other hand, the resolution of the image depends upon the number of pixels. In the above-described JP-A No. 4-323640, one image divided into subdivisions is exposed with pixels being two-dimensionally displaced by one and a half pitch, thereby making it possible to obtain twice the resolution by a rough calculation.
In this case, when a part of the pixels is defective, there is a possibility that the amount by which light is transmitted through the pixels cannot be controlled to be a desired value and may be different from the amount of light obtained from the density of an original image. Particularly, such defective pixels have so-called black point defects in which they are fixed in a state in which light is not transmitted through the image in the least or so-called white point defects in which they are fixed in a state in which light is transmitted through the image in a completely clear state.
As a result, a point having the density which is different from that of its periphery is revealed in part of the image. Particularly, in a case in which a pixel having a white point defect exists in an image, whose color is close to white, on the photosensitive material, or a pixel having a black point defect exists in an image, whose color is closed to black, such defective pixels become remarkable, thereby resulting in deterioration in quality of the image.
In addition to the above-described prior arts, there have been proposed, as the related art of the present invention, a liquid crystal display (see Japanese Patent Application Laid-Open (JP-A) No. 5-134268) having a fourth liquid crystal display panel for reproducing an image of spectrum or the spectrum of any one of three primary colors; an image display device (see Japanese Patent Application Laid-Open (JP-A) No. 5-313118) having at least one electro-optic modulating element for correcting defects, only one of light outputs of the electro-optic modulating element and an original electro-optic element for display of an image being introduced in a projection optical system; and the like.
In view of the above-described circumstances, it is an object of the present invention to provide an image exposure method using a display panel, which, when a defective pixel whose density (an amount of transmitted light or reflected light, or an amount of emitted light) cannot be adjusted exists and its position can be specified, the defective pixel is corrected by using the density (an amount of transmitted light or reflected light, or an amount of emitted light) of pixels around the defective pixel and an abnormal density condition in the shape of dots on the photosensitive material, which is caused by the defective pixel, is made unmarked accordingly, so as to prevent deterioration in quality of an image.